The invention relates to judging of the long jump and triple jump events in track and field.
In the long jump and triple jump events in track and field, it is necessary for a judge to determine whether or not each competitor has initiated his jump prior to crossing a "foul" line (also known as a scratch line). If any portion of a competitor's foot extends beyond the foul line or makes a mark after the foul line when jumping, then the jump is not measured.
It has been very difficult for track and field judges to accurately determine whether the leading portion of an athlete's foot has crossed the foul line. This difficulty arises from the high rate of speed with which athletes approach the foul line for their take-off. It is thus difficult to determine whether a leading portion of one of the feet of the competitor crosses the foul line before the foot leaves the ground.
Previously, a layer of a deformable substance known as plasticine or the like was laid down on a board positioned immediately beyond a jumping or take-off board. However, such a film layer must be repeatedly smoothed down whenever a competitor fouls and leaves an imprint thereon. Such a prior art system is also inaccurate, since an entire toe portion of the athlete's foot may not be in direct contact with the ground, but might be slightly raised from it when he takes off for his jump, thus not leaving a proper imprint in the film layer. Variations in style by various jumpers thus may result in inconsistent foul calling. Furthermore, variations in shoe type may also affect whether or not the shoe makes an accurate mark in the deformable layer used for foul detecting.